free calls to india/other countries through airtel

Making free calls to india/other countries without affecting your account balance is easy in case of airtel by a simple trick ;but actually it is not a trick it is the account number provided by airtel for its employers.For making calls to india through their network do the following:
1.Dial the number 1802103
2.you will hear the following message "please dial the ten digit account number followed by # key"
3.enter the number 0006105262# the last 4 digit of a number changes so try any other 4 numbers and after a number of attempts your code will be accepted.
4.Enjoy free std and isd through airtel.
5.The account number have a lifetime of 1 or 2 hours.So utilize it effectively.